Question

How did U.S. entry into WWI on the Western Front turn the tide of the war in favor of the Triple Entente/Allied Powers (France, Great Britain?)

Answer 1

The major shift in the World War I happened in 1917 almost 3 years into the war once the United States under President Wilson decided to join battle. The reason for this shift was the sheer number of American troops that landed in Europe in a very short time after the announcement. It is estimated that close to 10,000 men started arriving each day to help the Triple Entente as they were called defeat Germany at its own game. Germany had not bargained for such a swift deployment of a large number of troops by the US in Europe.